The sites of the embryos of man and other mammals are signs of similarity

Any organisms during individual development repeat the forms of their ancestors according to the law of germinal similarity or the law of Karl Baer. So, human embryo has many similarities with vertebrates, including representatives of mammals.

Similarities in the context of embryogenesis

The most obvious resemblance to mammals is that the fetus passes through all stages of development of intrauterine. It is also important that, being born, the child is a copy of an adult organism, but its size is much smaller than a sexually mature individual.

During the period of embryogenesis in the germ of both a person and a mammal, a chord is formed. This is, as it were, an beginnings of the spine. Further similarities begin to appear only at 6 weeks of life. At this time, mammary glands begin to develop at the embryo. Rollers are formed in the soft sky.

From 6-7 weeks, the tail section is formed. The fetus is already noticeable by the tail of the tail, which includes 8-9 vertebrae. However, by 3 months, the outer part of this department is degrading and, in the end, disappears. Only 2-4 vertebrae is preserved, which are growing and becoming a building material for the coccyx. At this time, the thumbs on the legs of the fetus are shorter than the rest and are located at an angle, like in anthropoid monkeys.

The digestive tract, lightweight. A few shells are formed around the fetus. On one, outgrowths are formed, in shape resembling villi. They become one with a fabric that consists of the uterus. So the placenta appears.

A little later the heart acquires more and more similarities with the heart of mammals. A partition appears, thanks to which it becomes fourchamber. In this case, the body temperature of the fetus is constant.

Later, already at 7 months, the embryo has the features of primates. At this time, his body is completely covered with thin hair that disappears by 9 months.

Rudiments

In the embryo of a person, in the process of embryonic development, rudiments also appear organs that do not benefit a person, but helped their ancestors survive. From mammals of the fetus, the tail muscle of Extensor Coccygis gets, which ensured the movement of the tail, many nipples on the body that disappear closer to 9 months of development.

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